1. Field of the Invention
The present invention relates to image-quality determination methods, image-quality determination apparatuses, and image-quality determination programs for evaluating the quality of an image printed on a recording medium by an image forming apparatus, such as a printer, a copier, or an ink-jet printer.
2. Description of the Related Art
It is known that the quality of characters printed in electrophotography deteriorates due to character thickening or thinning caused by how toner attaches, due to scattering of toner fine particles, and due to mechanical vibration.
It is also known that the quality of characters printed in an inkjet method deteriorates due to ink blur, scattering of ink dots, and mechanical vibration when ordinary paper is used instead of special glossy paper.
When an electrophotographic or ink-jet image forming apparatus is developed or manufactured, it is necessary to evaluate the printing quality of the image forming apparatus.
Conventionally, skilled persons visually compare a printed material with a limit sample to evaluate the quality of printed characters and images. In other words, printed materials are conventionally evaluated by the visual sense of human beings.
Date-label-printing inspection apparatuses used in factory production lines only determine whether a product is acceptable or defective (whether characters can be identified or not), that is, determines one of two states, and cannot determine fine quality which falls in a gray area.
In a conventional evaluation performed using the visual sense of human beings, different inspectors may make different determinations, or an inspector may make different determinations for the same thing.
When a small image is evaluated by visual inspection, it is necessary to enlarge the image, and hence expensive equipment, such as an optical microscope or an instant camera system, is required. In addition, if the quality of printed characters needs to be evaluated at 10 locations in one printed material, it is necessary to position the microscope and the printed material, focus the camera, adjust the exposure, and develop and fix the film after capturing an image, 10 times. This is very troublesome.
Further, the date-label-printing inspection apparatuses used in factory production lines only determine whether a product is acceptable or defective, that is, determines one of two states, and cannot be used to determine which printed material has the best image quality among a plurality of printed materials.